DDSPSMC11_ — StatusCondition should have a singleton delegate

Because the DDS-PSM-C++ abandoned the factory pattern, you now have to instantiate your own StatusCondition object, and pass the Entity to which it applies as parameter to its constructor.

However, DDS spec states that each Entity can have only one StatusCondition, and the get_statuscondition operation is responsible for that. Since with the DDS-PSM-Cxx API I can repeatedly create a StatusCondition for the same Entity, I can potentially break the Singleton pattern.

I would suggest that we state explicitly that when you instantiate multiple StatusCondition objects to the same Entity, they all end up pointing to the same Delegate.